Question

The main cause of acid rain is the formation of mineral acids like ____ and ____.

Answer 1

Hint :Nature depends on the balance and it is true that some rains are naturally acidic which consist of a pH level of around 5.0 but human activities have made it worse. Generally, the naturally occurring acidic rain reacts with alkaline chemicals or non-acidic materials which neutralize the effect of acid. However, if the pH of rain is too low i.e., the acidic nature of water is too high, then these chemicals are not able to neutralize the acids and thus, causing harmful acidic rain.

Complete Step By Step Answer:
The acid is caused by a chemical reaction which begins when compounds like sulphur dioxide and nitrogen dioxide are released in the atmosphere. Sulphur dioxide and nitrogen dioxide dissolve in water very easily and can be carried very far by the wind. As these chemicals can rise high in the atmosphere, they mix and react with water, oxygen, nitrogen and other chemicals to form acidic pollutants which cause acid rain.
The major chemical reactions involved in the acid rain are as follows:
Formation of Sulphuric acid due to reaction of sulphur dioxide with water and oxygen:
Step-1: Formation of sulphur dioxide: $ S + {O_2} \to S{O_2} $
Step-2: Formation of sulphuric acid: $ S{O_2} + \frac{1}{2}{O_2} + {H_2}O \to {H_2}S{O_4} $
Formation of nitric acid from nitrogen dioxide:
 $ 3N{O_2} + {H_2}O \to 2HN{O_3} + NO $
Along with the formation of nitric acid, the nitrogen monoxide gas is also released which is the major reason for photochemical smog and causes acid rain.
Thus, we can conclude that the main cause of acid rain is the formation of mineral acids like sulphuric acid and nitric acid.

Note :
It is important to note that the acidic nature of normal rain is because of the presence of carbon dioxide in the atmosphere. The carbon dioxide gas reacts with water to form carbonic acid which has a pH of 5.6. The chemical reaction involved in the process is: $ {H_2}O(l) + C{O_2}(g) \to {H_2}C{O_3}(aq) $ .